You will use this lab to plot the SMR data for the crayfish for the lab. Email me your SMR data, and I will post it on this website. The calculations might be tricky, but just email me if you have any question.
Convert the Standard Solution you used (from the buret) into O2 concentration for each control temp, and for the cold/warm big and small crawfish (so 6 total).
Calculate the amount of O2 in the different jars. For this, you have to multiply the concentration of the O2 in the control with the amount of liquid in the control (in Liters). The jars held 240mL (minus any crayfish), but you'll have to convert the final amount into liters* (so 240 mL = .24 L). When calculating the amount of liquid in the jars with crayfish, just subtract 1mL for each 1 gram of crayfish (so if the crayfish weighed 1g, then you would have 240-1=239, which is 239 mL = .239 L). Then multiply the amount of liquid with the concentration of O2 for that particular crayfish (or, if you are calculating the amount of O2 for the control, use the control O2 concentration). So the O2 concentration you are using in this multiplication will not be the same for the control and the sample.
Remember, this amount gives you an amount of O2, for any jar. If the jar had a crayfish in it, it's the amount of O2 that is left in the jar after the crayfish had used some of it. So the control amount of O2 should be larger than the amount of O2 for the crayfish.
Once you have the amount of O2 in the different jars (you should have 6 values of different O2 amounts), you can see how much O2 was consumed by the crayfish by comparing the amount of O2 in the control with the amount of O2 left in the crayfish jar. When you are done, you should have 4 values.
So, for example, the amount O2 consumed in the warm crawfish will be this: the amount of O2 in the warm crawfish minus the amount of O2 in the warm control. This difference will give you the amount of O2 consumed.
Use this amount of O2 consumed for the big and small warm/cold crawfish (4 values total), to calculate the SMR. SMR is in O2/g/h, so take your O2 amount, and divide by the weight of the animal (in grams) and then divide that result by the amount of hours (30 minutes = .5 hours).
Here is an example. Let say I used 3 mL of the standard solution after I titrated my cold small crayfish after 35 minutes (or 35/60 hours = .58 hours). I divide this by the standard solution number (something like 1.43?), and I get 2.2 O2 ml/L. This is my O2 concentration for the jar I am working with. I then have to figure out the volume of water in the jar with the small cold crayfish. The jar holds 240 mL This crayfish weighs 2 g, so this displaces 1 mL of water in the jar. The volume of water in the cold crayfish is 240 minus 2, or 238 mL. I convert this to L, using 100 mL = .1 L. Then, I take this volume in Liters and multiply it by the O2 concentration I calculated from the standard solution that I used when I titrated the sample from the cold crayfish jar. This number is 2.2, so 2.2 mL/L times .238 L gives me something like .5 mL of O2 in the jar with the cold crayfish. This is the O2 in the jar, after the crayfish sat for 30 minutes metabolizing the O2. I can do this same round of calculations, starting with the standard solution I used for the control jar sample (not the same as the amount of standard solution used for the cold crayfish sample), and figure out the O2 was in the cold control jar. Lets say it's .6 mL O2 (I'm making these numbers up, by the way). If I find the difference between the control jar and the experimental jar, then I can see how much O2 is "missing" from the jar due to the crayfish "breathing" it in. So .6 minus .5 is .1. This is gives me .1 O2 mL consumed for the cold small crayfish. SMR is the amount of O2 used by an organism, taking into account how long the organism was metabolizing and how big the organism actually is. So I can take this amount of O2 consumed and divide by how many grams the small crayfish weighs (2 g), and then divide that answer by how many hours the small crayfish experiment lasted (.58 hours). I do this and I get .086 O2/g/h as my SMR. I can do this entire process again for the small crayfish in the warm water, and for the big crayfish in the cold and warm water. Then I can put this info in the table on p. 100, and plot the SMR data on the log-log graph.
Email me this data (all the info you have on p. 100 in your lab manual). This table is tricky, because in one row, it will ask for the control O2 concentration, and (in the first, smaller data table that you won't turn in) your control O2 concentration were not listed in the same row as your crayfish info. So for the table on p. 100 that you will turn in, for 2 animals you should have just 2 lines filled out, one row for each crawfish.
*When you are calculating your SMR, be sure to convert the mL volume of your jar into Liters. So 100 mL = .1 L. You use this number, when you multiply the total volume of water (in Liters) by the O2 concentration. Then you can calculate your SMR using the same formula.
Lab 8 - Metabolism
I tried to record what I talked about in the intro to the crab lab. If you want to listen to it, here it is: Intro to Crab lab.docx
Temperatures:
low temp: 22 degrees C, high temp 32 degrees C.CRAWFISH LAB HINT:
Calculating the crayfish SMR.pdf -- This is a file helping you calculate the SMR data. I've also explained it below:
You will use this lab to plot the SMR data for the crayfish for the lab. Email me your SMR data, and I will post it on this website. The calculations might be tricky, but just email me if you have any question.
Here is an example. Let say I used 3 mL of the standard solution after I titrated my cold small crayfish after 35 minutes (or 35/60 hours = .58 hours). I divide this by the standard solution number (something like 1.43?), and I get 2.2 O2 ml/L. This is my O2 concentration for the jar I am working with. I then have to figure out the volume of water in the jar with the small cold crayfish. The jar holds 240 mL This crayfish weighs 2 g, so this displaces 1 mL of water in the jar. The volume of water in the cold crayfish is 240 minus 2, or 238 mL. I convert this to L, using 100 mL = .1 L. Then, I take this volume in Liters and multiply it by the O2 concentration I calculated from the standard solution that I used when I titrated the sample from the cold crayfish jar. This number is 2.2, so 2.2 mL/L times .238 L gives me something like .5 mL of O2 in the jar with the cold crayfish. This is the O2 in the jar, after the crayfish sat for 30 minutes metabolizing the O2. I can do this same round of calculations, starting with the standard solution I used for the control jar sample (not the same as the amount of standard solution used for the cold crayfish sample), and figure out the O2 was in the cold control jar. Lets say it's .6 mL O2 (I'm making these numbers up, by the way). If I find the difference between the control jar and the experimental jar, then I can see how much O2 is "missing" from the jar due to the crayfish "breathing" it in. So .6 minus .5 is .1. This is gives me .1 O2 mL consumed for the cold small crayfish. SMR is the amount of O2 used by an organism, taking into account how long the organism was metabolizing and how big the organism actually is. So I can take this amount of O2 consumed and divide by how many grams the small crayfish weighs (2 g), and then divide that answer by how many hours the small crayfish experiment lasted (.58 hours). I do this and I get .086 O2/g/h as my SMR. I can do this entire process again for the small crayfish in the warm water, and for the big crayfish in the cold and warm water. Then I can put this info in the table on p. 100, and plot the SMR data on the log-log graph.
Email me this data (all the info you have on p. 100 in your lab manual). This table is tricky, because in one row, it will ask for the control O2 concentration, and (in the first, smaller data table that you won't turn in) your control O2 concentration were not listed in the same row as your crayfish info. So for the table on p. 100 that you will turn in, for 2 animals you should have just 2 lines filled out, one row for each crawfish.
*When you are calculating your SMR, be sure to convert the mL volume of your jar into Liters. So 100 mL = .1 L. You use this number, when you multiply the total volume of water (in Liters) by the O2 concentration. Then you can calculate your SMR using the same formula.
Data (this data is good, write it down):